The present disclosure relates generally to image processing and, more particularly, to systems and methods for initial image processing in an image sensor before additional processing in an image signal processor.
This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present disclosure, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
Digital imaging devices have become increasing popular due, at least in part, to such devices becoming more and more affordable for the average consumer. Further, in addition to a number of stand-alone digital cameras currently available on the market, it is not uncommon for digital imaging devices to be integrated as part of another electronic device, such as a desktop or notebook computer, a cellular phone, or a portable media player.
To acquire image data, most digital imaging devices include an image sensor that provides a number of light-detecting elements (e.g., photodetectors) configured to convert light detected by the image sensor into an electrical signal. An image sensor may also include a color filter array that filters light captured by the image sensor to capture color information. The image data captured by the image sensor may then be sent to an image processing pipeline (e.g., image signal processor (ISP)), which may apply a number of various image processing operations to the image data and generate a full color image that may be displayed for viewing on a display device, such as a monitor. In general, the image sensor may send the image data to the ISP via a sensor-to-ISP data link. As such, for still image data, the image sensor captures an image and sends the image as raw image data to the ISP via the sensor-to-ISP data link. The ISP and the sensor-to-ISP data link may generally be able process the raw image data at a standard rate such that it will effectively display the high-resolution image on a display device.
Video image data, on the other hand, include a great deal more amount of data as compared to still image data. For instance, video images may include images captured at 30 to 60 frames per second (i.e., raw video data). Certain professional camera devices may process high-resolution raw video data in the ISP before downscaling the video data to a typical output resolution (e.g., 1920×1080). Processing each frame of the raw video data through the ISP, however, consumes significant processing and power resources. To avoid, many consumer camera devices may reduce the effective resolution of raw video data in the sensor before transferring the raw image data to the ISP.
A common way to reduce the effective resolution of the raw video data is by “binning” the raw video data. Binning may include averaging adjacent groups of same-color pixels in each frame of the raw image data to make an effective lower-resolution sensor. For example, on a 4000×3000 pixel sensor, the sensor may be programmed to bin each 2×2 group of pixels and reduce the effective resolution of the pixel sensor to 2000×1500, which the ISP might crop and/or scale to a resolution of 1920×1080. Although the ISP and the sensor-to-ISP data link may more efficiently process the high-resolution images and video images received by the image sensor using the binning process, the quality of resulting video images may be unsatisfactory.